[unreadable] I am a faculty member at the University of Califomia, San Francisco (UCSF) studying the cell biology of melanocytes. The University has a vibrant and productive community of internationally recognized cell biologists interested in problems of membrane trafficking. Part of my research development plan will consist of interfacing with the cell biology community and other UC researchers through formal and informal mentoring and participation in journal clubs, seminars and data clubs. In addition to experts in my field of interest, UCSF has many researchers of high caliber in other fields, from whom one can learn new techniques and experimental approaches as needed. Numerous core facilities are available and easily accessible. I study a specialized cell, the melanocyte, which is found in the skin, eye, ear and meninges, and is a cell that produces the pigment melanin. I am analyzing cellular and molecular defects caused by the Hermansky-Pudlak Syndrome (HPS), a genetic disease that causes abnormalities in melanosomes, an organelle in melanocytes in which melanin is synthesized and stored. Individuals with HPS have vision defects, prolonged bleeding, and are pigment diluted compared with family members. HPS-affected individuals can also develop colon and lung disease, which can be a cause of early death between 30 and 50 years of age. HPS is an autosomal recessive disorder, caused by a single defective gene, but several different genes, when defective in isolation, can give rise to HPS. The HPS genes are found in humans (6 genes identified to date) and mice (16 non-allelic genes), and are ubiquitously expressed. Although several HPS genes have been identified, how they work remains unknown. My long-term goals are to understand how cell specific functions are determined and regulated, and how dysregulation of cell specific organelles leads to significant disease. This proposal focuses on the immediate goals of determining the functions of selected HPS gene products in melanocytes and learning how these ubiquitous proteins regulate melanosome biogenesis and function. [unreadable] [unreadable] [unreadable] [unreadable]